Electrical manipulator



June 1, 1954 ELECTRICAL MANIPULATOR Filed June 28, 1951 Z74 J6 J8 )l ull R. C. GOERTZ ET AL 13 Sheets-Sheet l IN V EN TORS J jlrlazzd 6T Gael ozzczld F Uecker' June 1, 1954 Filed June 28, 1951 HHIIII) HIM R. C. GOERTZ ETAL ELECTRICAL MANIPULATOR 15 Sheets-Sheet 2 INVENTORS.

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ELECTRICAL MANIPULATOR Filed June 28, 1951 13 Sheets-Sheet 3 INVENTORS. gal zrzozzd C 6067"? arzald F I/ecke June 1, 1954 R. c. GOERTZ ET AL 0 ELECTRICAL MANIPULATOR June 1, 1954 R. c. GOERTZ ET AL 2,679,940

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ELECTRICAL MANIPULATOR Filed June 28, 1951 13 Sheets-Sheet 6 FIE-1E1 June 1, 1954 R. c. GOERTZ ET AL ELECTRICAL MANIPULATOR 13 Sheets-Sheet 8 Filed June 28, 1951 INVENTORS. Ja s/2710211 C fiber-g June 1, 1954 R. c. GOERTZ ETAL' ELECTRICAL MANIPULATOR 13 Sheets-Sheet 9 Filed June 28, 1951 I N VEN TORS mbrrd (fiver-6 Jozraldf'l/ecker NWN MAR I g J l5 Sheets-Sheet 10 Filed June 28, 1951 INVENTORS.

Jarzalaf' June 1, 1954 Filed June 28, 1951 R. c. GOERTZ ETAL 2,679,940

ELECTRICAL MANIPULATOR l5 Sheets-Sheet 11 J64 f2 INVENTORS:

June 1, 1954 R. c. GOERTZ ET AL 7 ELECTRICAL MANIPULATOR Filed June 28, 1951 15 Sheets-Sheet l2 INVENTORSI :2 7710786! C 606)"! rald F l/ec/(eF BY June 1, 1954 R. c. GOERTZ ET AL ELECTRICAL MANIPULATOR Filed June 28, 1951 15 Sheets-Sheet l3 Patented June 1, 1954 UNITED STATES PATENT OFFICE ELECTRICAL MANIPULATOR Application June 28, 1951, Serial No. 234,128

14 Claims. 1

The present invention relates to a device for remote control manipulation. More particularly it pertains to an electrically operated remote control manipulator.

Recent developments in radioactive substances have resulted in the increased importance of remote control devices because of the detrimental effect to human welfare of exposure to radioactivity. With such a device an operator can perform his maneuvers with impunity from behind a protective wall, observing his work indirectly. Application of remote control devices, however, is not confined to the radioactivity field for they are readily adapted to use in other fields of endeavor, such as laboratories conducting research in bacteria, noxious matter and the like.

The present invention provides a remote control manipulator which is capable of performing extremely delicate operations with accuracy in a confined work space.

The invention will be understood from the following description and the appended drawings, in which:

Figure 1 is a perspective view of the manipulator, showing a vertical tube, a carriage by which said tube is disposed on a cantilever, and a mounting frame by which the assembly is mounted to horizontal rails on a wall;

Figure 2 is a rear elevational view of the mounting frame by which the manipulator is mounted on the rails on the wall;

Figure 3 is a side view of the frame partly in section;

Figure 4 is a rear elevational View of the carriage of Figure 1;

Figure 5 is a side View of the carriage, taken on the line 5-5 of Figure 4;

Figure 6 is a horizontal sectional View taken on the line 55 of Figure 4;

Figure 7 is a fragmentary sectional view taken on the line l'l of Figure 4:;

Figure 8 is a vertical view in section of a gear assembly at the lower end of the tube, taken along the line 8-8 of Figure (to be described below);

Figure 9 is a sectional view taken on the line 9-9 of Figure 8;

Figure 10 is an elevational view of the gear assembly and tongs attached thereto;

Figure 11 is a plan view partly in section taken along the line ll-H of Figure 10, showing the manner in which the tongs are attached to the gear assembly;

Figure 12 is a sectional view taken along the line [2-42 of Figure 11;

Figure 13 is a vertical sectional view taken on the line l3l 3 of Figure 12;

Figure 14 is an elevational view of a diiferential gear assembly at the upper end of the tube, showing in section the housing for said assembly which is shown in elevation in Figure 1;

Figure 15 is a plan view partly in section taken along the line I5l5 of Figure 14 of the differential gear assembly shown in Figure 14;

Figure 16 is a horizontal sectional view taken on the line Iii-i6 of Figure 14;

Figure 17 is an end view partly in section of the differential gear assembly taken on the line llli of Figure 14;

Figure 18 is a vertical sectional View on the line l8l8 of Figure 14;

Figure 19 is a vertical sectional view taken on the line l9l 9 of Figure 14;

Figure 20 is a vertical sectional view of a limit switch for an elevation motor taken on the line 20-23 of Figure 15; and

Figure 21 is a schematic wiring diagram for the manipulator.

The manipulator constituting the embodiment of the invention to be described is generally indicated at 3B in Figure 1. It comprises a supporting unit generally indicated at 32, a carriage 34, tongs 36 having a pair of movable jaws t8 and a differential gear assembly generally indi cated at 40.

The supporting unit 32 comprises an elongated vertical tube 42, a cantilever it, and a frame Alt which is movable horizontally along a wall 48 in a manner to be described below. By virtue of the supporting unit 32, the manipulator 38 is adapted to move in three linear directions. The tube 42 moves vertically with respect to the carriage 34 along its longitudinal axis; the carriage 34 moves horizontally along the cantilever a l; and the entire assembly is adapted to move horizontally along the wall 48.

Considering Figures 2 and 3, the frame it is substantially triangular in shape and is provided with a sleeve 59 integral therewith, the inside diameter of which is affixed, as by sweating, to one end of the circular cantilever i i, and thereby holds it fixedly in a horizontal position. The frame 4% is mounted on an upper horizontal rail 52 and a lower horizontal rail 56, which are secured to the wall it, by means of a pair of upper wheels 56 and a lower wheel 58. Movement of the frame 46 along the wall is provided by a friction wheel Ell which rolls along the surface of the upper rail 52 facing the wall it, serving to retain the assembly on the rails. The

friction wheel 60 is driven by a motor 62, secured to the frame 46, which is geared by means of a conventional reduction gear box St to a shaft 6G. In turn, the shaft 56 is held in place by a journal 68 that is integral with the frame lit. Secured to the top of the shaft 56 is the friction wheel 63. On the same horizontal level with said friction wheel is a roller I l which, together with a pair of back-up wheels 12, serve to maintain constant alignment of the wheels 56 and 53 with the rails 52 and 56, respectively, no matter what torsional force is applied by the manipulator 38 to the cantilever i l. The back up wheels I2 are secured to a strap "Hi and roll along the surface or the rail 52 opposite that contacted by the wheel 5i and the roller It.

The carriage 3 (Figures 4-6) comprises a front housing plate to and a back housing plate 82 which are disposed parallel to each other on opposite sides of the cantilever i l. These plates are held rigidly in place by a top plate 3 9 and a bottom plate 85 together with end plates 33 and Q8 (Figure 4) which are apertured at 2 to accommodate the cantilever 44.

Secured to the front plate 86 are two motors 9t and 96 (Figure 5). The motor as moves the carriage Bil horizontally along the cantilever 44, while the motor 95 actuates the tube 32 up and down with respect to said carriage. With respect to the horizontal movement 01 the carriage 34 along the cantilever 4t, reference is made to Figures 4 and 5 in which two shafts 98 and 136 are seen to be journalled in the front plate 88 and the back plate 32 near the top of the carriage. To the shafts 98 and I853 are secured rollers I52 and IE4, respectively, centrally between the plates 88 and 82. Each roller is provided. with a knife-edge periphery in order to fit a V-groove its extending longitudinally along the top of the cantilever fi l. By virtue of this arrangement the carriage 34 is moved in either direction along the cantilever lit by the reversible motor 9:; which is provided with a reduction gear box I68 and which is coupled in a conventional manner to the shaft I95. As a precaution against angular rotation of the carriage 35 about the longitudinal axis of the canti lever 45, two rollers H2 and H4 are provided to fit a v-groove Ill disposed along the bottom side of the cantilever =34 opposite the groove I655. The rollers H2 and H4 are similar to the rollers m2 and EM. The roller H2 is centrally disposed between the plates 333 and 82 and directly below the roller 582, and is mounted on a shaft II'c that is fixed in a U-shaped shackle IE8. The shackle I58 in turn is pivoted on a shaft I25, the ends of which are secured to the plates 88 and 82. Two springs I22 are provided beneath the free end of said shackle in order to serve as shock absorbers for the roller H2 and to hold it in secure engagement with the groove III Similarly, the roller H4 is mounted in the groove H and is secured to a shaft :24 (Figures and '7), the ends of which are disposed in a shackle I26 directly above a pair of springs I28 which serve as shock absorbers for said roller. Likewise, the shackle 126 is pivoted on a shaft I39 within a sleeve bearing ISI (Figure 7). The shaft I36 extends on either side through the plates 30 and 82 in which said shaft is journalled. To the extremity of the shaft 38 extending beyond the plate 82 is affixed a pinion I32 the purpose of which will be described below. The other end of the shaft I38, extending beyond the plate 89, is coupled in a conventional man- 4 nor to a reduction gear box I3 3 on the reversible motor 96.

Adjacent the back plate 82 the tube 42 is vertically mounted on the exterior of the carriage 3t. Extending perpendicularly from the plate 82 three guide rollers MG, 1 22 and Mt are disposed on shafts I46, I48 and 150, respectively, to maintain the tube t2 in vertical position. The guide roller I40 is disposed directly above the guide roller hi l on the same side of the tube 42, while the guide roller I42 is disposed on the opposite side of said tube at a location substantially half way between guide rollers M0 and I44. (Figures 4, 5 and 6.) On the side of the square tube 42 facing the pinion I32 is secured a rib I52 which furnishes a support for an elongated rack I54 which is engaged by said pinion. Hence, the tube 42 is adapted to be moved up and down by the reversible motor driving the pinion I32 on the rack I54, said tube being guided in its vertical motions by the guide rollers I40, Hi2, and I44. In order to reduce the load on the motor 95 a suitable spring I56 is secured at the upper end to a bracket 158 extending from the plate 82. At the lower end said spring is secured to a point near the lower end of the tube 42 (Figure 10). By virtue of the spring I58 the motor 95 is relieved of much of the weight attached to the tube 42.

The rectangular tube 42 serves as a housing for the means which operatively connect the difierential gear assembly 33 to the tongs 36, which means comprise three concentric tubes IF, I62 and IE5 (Figure 8). These tubes are round, the tube I60 having the smallest diameter and the tube I84 having the largest diameter. The lower end or tube 169 extends below that of tube I62 which in turn extends below that of tube IE4. The tube I63 is designated as the azimuth tube. The tube I52 is designated as the elevation tube. And the tube Iiii is designated as the twist tube. The tongs 36 are capable of three directional rotation, namely, azimuth or rotation in a plane normal to the vertical axis of the tube &2; elevation or rotation in a plane passing through the vertical axis of said tube; and twist or rotation of the tongs 36 about their own longitudinal axis. The manner in which these various rotations are achieved either singly or in combination will be described below. Likewise the manner in which the jaws 38 of the tongs 36 are opened and closed will be set forth.

Attached to the lower end or" the azimuth tube IE0 is a knuckle I63 (Figures 8 and 9) the upper portion of which is annular to accommodate said tube and the lower portion of which is bifurcated. Above the knuckle I68 is abevel gear ill] that is secured to the lower end of the elevation tube I52. Concentrically disposed about the gear H6 is a bevel gear I12 which is affixed to the lower end of the twist tube I64. Between the contiguous surfaces of the knuckle I68 and the gear and the gear H2 are disposed a plurality of ball bearings I'M and I16, respectively, which make for smooth operation between these parts. To the lower end of the rectangular tube 42 is attached a bushing I18, the upper portion of which is rectangular and the lower portion of which is annular in order to accommodate an annular bearing I30. The bearing I86 surrounds the upper end of the gear I72 thereby holding the assembly of tubes and gears centrally within the tube 42.

The means by which the tongs 36 are attached to and rotated about the lower end of the manipulator is shown in Figures 8 to 13. In the biiurcated portion of the knuckle I68 there are two apertures I82 and I84 oppositely disposed and normal to the axis of the tube 42. Needle bearings I86 and I88 are mounted in the apertures I82 and I84, respectively, in order to support a shaft I98. A yoke I92 is mounted on the shaft I96 on bearings I94 and I96 on each side of the knuckle I68. As shown in Figure 11 the yoke I92 has a stem I96 integral therewith and extending in a plane normal to the shaft I 98. Two bevel gear wheels 260 and 282 are mounted on the shaft I90 and engage the gears I76 and I12, respectively. The wheel 280 is contiguous to one arm of the yoke I92 and is attached thereto by a screw 263. By such attachment the yoke I92 is caused to rotate about the shaft I96 by the wheel 298. The gear wheel 280 is smaller than the gear wheel 282, and the former is mounted on the bearing I96 while the latter is tightly secured to the shaft I98. In order to retain the shaft I98 in place a conventional split ring 264 is secured to the end opposite the gear wheel 282 which is adjacent a spring washer 266, the periphery of which contacts the yoke I62.

At the center of the knuckle I68 in the bifurcated portion a pulley 298 is mounted loosely on the shaft I90, said pulley having an aperture greater than the diameter of said shaft (Figure 9). In this manner the pulley 283 more easily accommodates a cord 2I0 which closes the jaws 38 of the tongs 36. The upper end of the cord 2I8 is secured to a cable tube 2I2 having a slot 2I3 at the lower end through which said cord is passed and knotted so that it is sustained in a taut position. The purpose of the cable tube 2 I2, which extends centrally of the tube I68, is to reduce the loss of tautness due to stretching which would occur if the cord 2I0 extended throughout the length of the tube I60.

Considering more particularly the manner in which the tongs 36 are joined to the above-described assembly, attention is directed to Figure 11. In order to rotate the tongs 36 about their longitudinal axis a bevel gear 2I4 having a hub 2I6 integral therewith is mounted rotatably on the stem I 98 of the yoke I92 and meshes with the gear wheel 282. In this manner rotation of the tube I64 (Figure 8) is transmitted through the gear I12 and the gear wheel 202 to the gear 2I4. As shown in Figures 12 and 13 the outside surface of the hub 2I6 is squared with rounded corners in order to transmit rotational movement from the gear 2I4 to the tongs 36. Around the outer portion of the hub 2 I 6 is a neck 2 I8 by which the tongs 36 are secured thereto.

As was mentioned above, the hub 2 I6 is rotatably disposed on the stem I 98 of the yoke I92 where it is retained by a split ring 220 near the end of said stem remote from the yoke I92. The stem I98 serves as a sleeve for a rod 222 which is slidably disposed therein along its longitudinal axis and one end of which extends beyond the aforementioned end of said stem. Along a portion of the rod 222 is a longitudinal slot 224 into which extends a pin 226, one end of which pin is secured within the stem I98. Hence, the length of the slot 224 establishes the distance through which the rod 222 may be moved. Through the center of the rod 222 passes the cord 2I0 which is knotted at the end remote from the pulley 268 and held taut against a reduced portion of the stem bore. At the same end a cone 228 having a central bore 238 is mounted on a bearing 232 which in turn is held in place by a split ring 234.

against the bearing 232 on one end and against the stem I98 on the other end whereby the cone- 228 is held away from the stem I98 by a distanceequal to that of the length of the slot 224 whentension is released in the cord 2I8.

The tongs 36 comprise the pair of jaws 38 and. a support member generally indicated at 249' which includes a cam lock assembly, generally indicated at 238 (Figures 12 and 13) for attaching said tongs to the hub 2I6 of the gear 2M. The support member 246 is generally rectangular in shape and includes a transverse element 242; between two parallel longitudinal elements 244 and 246 which are integral with a transverse member 248. Being oppositely disposed the elements 244 and 246 are slotted longitudinally be-- tween the element 242 and the member 248 in order to receive the jaws 38 that are pivoted 0pposite to each other on pins 250 and 252. In this manner the jaws 39 are adapted to be opened by a hair spring 254 disposed therebetween and adapted to be closed when the cone 228 is retracted by the cord 2I8, whereby said cone bears against a pair of rollers 256 and 258 disposed on the bifurcated ends of said jaws. In order to facilitate the grasping of an object with the jaws 36, the grasping ends may be equipped with sleeves 268 of soft material such as rubber or friction tape.

The tongues 33 are attached to the hub 2I6 by means of the cam lock assembly 233. This assembly, similar to a jewelers lock, is adapted for easy attachment or detachment. It ccmprises the support member 248, a cap 232 at-- tached thereto on the end adjacent the gear 2 I4, and an annular cam 264 having an opening 266 in one side thereof large enough to pass the hub 216. Along the longitudinal axis of the tongs 36 a slot 266, slightly greater than the hub 2I6, is disposed in the member 248 and the cap 262 and is open to one side thereof in order to receive said hub. In a plane normal to the axis of the slot 266 is an annular niche 268 having a pair of oppositely disposed shoulders 213. This niche is formed by the member 248 and the cap 262 and registers with the neck 2I8 around the hub 2I6 when said hub is disposed in the slot 266. By aligning the opening 265 in the cam 264 with the slot 286, the hub 2H5 may be inserted wholly into said slot and the cam 264 rotated within the niche 268 by means of a knurled surface 2'I2 on the periphery of said cam until said hub is locked in place. At the same time the rollers 256 and 258 at each. end, of the jaws 38 contact the surface of the cone. 228.

As was pointed out above, the tongs 36 may be manipulated into any desired position on they lower end of the tube 42. These manipulations: include three directional rotations in addition to lineal movement. The rotations are separately transmitted to the tongs 36 by means of the concentric tubes I68, I62, and I64, the upper ends of which extend into the differential gear assembly 46. As shown in Figure l, the gear assembly 48 is attached to the top of the tube 42 by means or a pair of brackets 280. The brackets 289 support a base plate 232 to which is attached a rectangular housing 284 (Figure 14). A plurality of inlets 286 are provided in said housing to receive a number of electric cables 288. These cables connect the manipulator to a convene tional control box, not shown in the drawings. However, attention is directed to the wiring diagram in Figure 21 in which various parts of the manipulator are shown connected to conventional switches in the control box. Further reference to Figure 21 will be made later. As shown in Figure 17, the base plate 282 is apertured at 299 in a location centrally disposed over the tube 42. Above the plate 282 directly over said aperture is secured a mounting support 222 which is centrally apertured at 29 1 in alignment with the aperture 290 for the passage of the tubes [6%, I62, and 16-; and the cable tube 2 it.

The outer tube I64, being the shortest of the three, is surmounted with a worm gear 296 that is secured thereto by a clamp 298. Integral with the worm gear 295 is a hub 309, the lower end of which is mounted in a bearing 362. In turn the bearing 382 is fitted into a circular recess 3%, the center of which is aligned with the center of the aperture 294 in the mounting support 292. in this manner the tube 554 is centrally disposed within the apertures 295 and 294. Extending above the upper end of the tube 186 is the upper end of the tube .62 to which is attached a worm gear 366 by means of a clamp 3E8. Similar to the worm gear 296, the worm gear 305 has an integral hub 1H0, the lower end of which is mounted in a bearing 312 that is disposed in a. circular recess 3M in the upper surface of the worm gear 298. Extending above the upper end of the tube I62 is the upper end of the tube I69 to which is mounted a worm gear 316 by means of a clamp M8. The worm gear 316 differs from the worm gears 39% and "296 in that the former includes an upper hub 32% and a lower hub 322. The lower hub 322 has a helical groove 324 about its outer surface. The lower end of the lower hub 322 is seated in a bearing 326 that is mounted in a circular recess 323 in the top surface of the gear wheel 396. Centrally disposed of the gear wheel 31% and the hubs 326 and 322 is a vertical bore 346 which is aligned with and communicates with the central tube ml. Through the bore 3% passes a cord 3&2 which is attached to the upper end of the cable tube 2 i2 in a manner similar to the cord 2N at the lower end thereof. The cord 3 12 passes over a pulley 344 which is mounted on a shaft 3% above the bore 343 and will be described more fully below.

As shown in Figures 14 and 1d the operating parts of the gear assembly is are mounted on several support elements. In particular a pair of C-shaped uprights 348 and 350 are secured at either end of the mounting support 292 perpendicular thereto. As shown in Figures 16 and 17, the uprights 348 and 350 are oppositely disposed on either side of the worm gears 295, 356 and 316. Secured to the top of these uprights is a bridge 352 which provides more rigid support therefor and, in addition, includes an annular protrusion 354 extending downwardly into the upper hub 328 of the worm gear 3H5. The center of the protrusion 354 is aligned with the bore 3 of said worm gear and with an aperture" 356 in the bridge 352 midway between the uprights 348 and 35!]. Through the aperture 35% passes the cord 342. Between the protrusion 354 and the upper hub 320 is disposed a bearing 358' that supports the worm gear 3E6.

One of the purposes of the uprights 348 and 355i is to provide support for three worms 3%, 362, and 364 which are mounted on and driven by shafts 366, 368, and 310, respectively. As

shown in Figures 16 and 1'7, the worm 36B meshes with the top worm gear 316 and the shaft 366, on which said worm is mounted, is journalled on either side thereof in a conventional manner to the upright 3&8. Directly below this is the worm 362 which meshes with the worm gear 356, and the shaft 368, on which it is mounted, is journalled on either side thereof in the upright S 28, similar to the shaft 366. On the lowest level the worm gear 296 meshes with the worm 384, and the shaft 310 on which it is mounted is journalled to the upright 2 56 in manner similar to the shafts 36B and 358 above described. It is pointed out that the worm 35 has a left-hand thread as distinguished from the right-hand threads on the worms 380 and 362 (Figure 14).

A limit switch, generally indicated at 312, is disposed on the outer surfaces of the uprights 348 and 358 between the gear wheels 36% and 3H5 (Figure 17) Being adapted to function with the helical groove 324 on the worm gear 3 I 6, the limit switch 312 comprises a bar 314, a lower microswitch 376, and an upper microswitch 318. Said microswitches are mounted on the upright sec in the same plane as the bar 3M so that the end of the bar disposed therebetween will actuate either a switch button 388 on the switch 3%, or a button 382 on the switch 31%. Being designed to function more or less as a first class lever, the bar 374 has a pivot pin 584 extending into the helical groove 324. At the end of said bar remote from the limit switches is disposed a pin 3% which extends in a direction opposite to that of the pivot pin 38-4 and into an elongated slot 398 of a pin retainer 392. The end of the bar Sis between the switches 3'16 and 318 is confined to vertical movement between said switches by a guide 35 3. The purpose of the limit switch 312 is to prevent the rotation of the gear Bit and the inner tube we to which it is attached beyond a given number of clockwise or counterclockwise revolutions which, if not inhibited, would cause the cords 2H] and 342 attached to either end of the cable tube M2 to twist, resulting in reduced resilience and, therefore, binding of the cords on their respective pulleys. For example, as the tube I69 is rotated in a counterclockwise direction, the pivot pin 3% follows the helical groove 324 downwardly, causing both ends of the bar 314 to drop until the pin 386 contacts the lower end of the slot 336 and the opposite end of said bar is depressed against the button sea of the switch 316. This cuts off the current to a motor 498 that turns the gear 315 (hereinafter to be described) it being only possible thereafter to operate said motor in the opposite direction. Likewise, when the tube 1-68 is rotated in a clockwise direction the pivot pin 384, following the helical groove 324, rises until the free end of the bar 314 strikes the button 382 of the limit switch 378. Since the number of turns on the helical groove 32 is sufiicient for practical operation of the manipulator and rotation of the tongs 36, an operator of the manipulator is not unduly limited in the number of turns in either direction which can be made. Under normal operation the tongs 38 will be turned a comparatively equal number of times in each direction whereby the pin 38:! asumes a central position on the helical groove 324, in which case the limit switches 376 and 318 will never actuate. Figure 21 indicates the manner in which the electrical connections are made.

Referring now'to Figures 14 and 15, other sup- 9 port elements may be considered in addition to the uprights 348 and 358. Attached to the base plate 282 substantially centrally thereof is a bracket base 395 extending transversely of said plate. Along one edge of the bracket base 386 parallel to the mounting support 292 is a bracket 398 secured to and normal to said base. To the other edge of the base 388 is attached a bracket 488 parallel to the bracket 398. A bridge 482 spans the brackets 388 and 488 at the top for increased rigidity. The brackets 398 and 488 are apertured at a number of places to receive conventional shoulder bearings 484.

The remaining support element is a motor mount 486 secured to the base plate 282, extending perpendicular therefrom and parallel to the bracket 488. The motor mount 498 is apertured in three places on axes parallel to the base plate 282 to accommodate three motors, namely, the azimuth motor 488, an elevation motor 418, and a twist motor 412, which motors are provided with shafts 414, 416 and 418, respectively. (Figure 16.) By way of orientation the azimuth motor 488 is adapted primarily to rotate the azimuth tube 188 which rotates the tongs 88 about an axis normal to said tube. The elevation motor 418 is adapted primarily to rotate the elevation tube 162 which causes the tongs 88 to rotate in a vertical plane passing through the axis of said tube. Finally, the twist motor 412 rotates the twist tube 164, twisting the tongs 56 about their longitudinal axis. The mechanism by which these rotations are accomplished includes the differential gear assembly 46 that is about to be described.

Secured to the end of each motor shaft 414, 418, and 418 is a bushing 428, 422 and 424, respectively, on which is mounted a pin clutch gear 428, 428, and 438, respectively. By means of a similar clutch pin 432 the gears 428, 428, and 438 are connected to a female pin clutch 434, 43 6, and 438, respectively. The pin clutch 434 is attached to the end of horizontal shaft 448 which extends through and is journalled in the brackets 488 and 398. To the other end of said shaft is mounted a female pin clutch 442 which, by means of a clutch pin 444, is connected to a male pin clutch 446 that, in turn, is mounted on the end of the shaft 366. By virtue of this assembly it is evident that the azimuth motor 488 drives the worm 388 which meshes with the worm gear 318 on top of the azimuth tube 168.

Between the brackets 888 and 488 are disposed two differential gears generally indicated at 448 and 456. These gears are conventional in design and have similar parts comprising an axial shaft 452, a box 454 integral with said shaft substantially centrally thereof, a pair of side gears 456 and 458 rotatably disposed on said shaft on either side of the box 454, and a cage generally indicated at 488. The cage comprises a shaft 462 which is perpendicularly mounted to the box 454, and a pair of cage gears 464 which are mounted to either end of the shaft 462 and each of which meshes with both side gears 456 and 458 on either side thereof. The shafts 452 of the differential gears 448 and 458 are journalled to the brackets 398 and 488 on either side of said gears and in alignment with motor shaft 416 and 416 to which they are linked by virtue of their connection to the female pin clutches 436 and 438, respectively. In addition spur gears 466 and 468 are secured to the side gears 456 and 458, respectively, of the differential gear 448. Likewise, spur gears 418 and 412 are secured to the side gears 456 and 458, respectively, of the differential gear 450.

Between the diiferential gears 448 and 458 is disposed a shaft 414, journalled to the brackets 396 and 488, and on which is mounted a spur gear 416 which meshes with the spur gears 468 and 412. Also a spur gear 418 is mounted to the opposite end of said shaft which end extends through the bracket 398. It is pointed out that the spur gears 466, 468, 418, 412, and 416 have equal dimensions.

The spur gear 488 meshes with a spur gear 488 secured to the shaft 448. Similarly the spur gear 418 meshes with a spur gear 482 mounted on a shaft 484 which is journalled to the brackets 398 and 488 and on one end of which is secured a female pin clutch 486. By means of a pin 488 this pin clutch is linked to a male pin clutch 498 that is secured to the end of the shaft 318. In addition, the spur gear 418 meshes with a spur gear 482 secured to a shaft 484 (Figures 14 and 18) which is linked to the shaft 368 by means of a pin clutch generally indicated at 495, similar in construction and parts to the pin clutches mentioned above. It is pointed out that the diameter of the ears 488 and 482 are equal to each other and have twice as many teeth as the gears with which they mesh (Figure 18). Also the gear 492 has twice as many teeth as the gear 418 which, in turn, is slightly larger than the gears 466, 468, 416, 412 and 418 for the reason that the lineal distance between the shafts 414 and 494 is slightly greater than the distance between the shafts 452 and 448. Sufiice it to say the purpose of the gears with the larger diameters is to reduce the speed by a factor of two in order to drive the worm gears 296, 386, and 316 at the unit speed of each of the motors 488, 418, and 412. Moreover, the unit speed of said motors is multiplied by a factor of two when transmitted through either of the differential gears 448 or 458, for reasons inherent in the operation of said gears and well known in the art.

Inasmuch as the assembly of gears interconnects the shafts 866, 868, and 318 by which separate directions of rotation are transmitted to the tongs 36, it is necessary to separately lock the shafts of each motor in place when one or two motors are being operated, in order to prevent rotation of the shaft due to the backlash of rotational friction of the operated motors. Accordingly, to each pin clutch gear 426, 428, and 488 (Figure 19), a pivot rack 495, 498, and 588, respectively, is attached. The racks 498, 498, and 588 are pivoted to the motor mount 496 by means of pivot pins 582, 584, and 586, respectively, and are held in engagement with their corresponding gear by means of a tension spring 588, 518, and 512, respectively. Solenoids 514, 516, and 518 are secured to the base plate 282 (Figure 14), and are connected in parallel (Figure 21) with the motors 418, 412, and 488, respectively. As shown in Figure 19 the solenoids 514 and 516 are directly linked to the pivot racks 498 and 588, respectively, while the solenoid 518 is indirectly attached to the pivot rack 498 by means of the pivot link 528. Hence when a given motor is actuated the corresponding solenoid disengages the pivot rack from the corresponding clutch gear, the remaining clutch gears being fixed in position by their corresponding pivot racks.

As shown in Figures 14, 15 and 20 a limit switch generally indicated at 522 is disposed on the motor mount 488. The limit switch 522 comprises a horizontal brace 524 secured to the motor mount 488, a switch actuator 526 pivoted at one end by a bolt 521 to said brace, limit switches 52!] and 530 attached to said brace on either side of said actuator, a lead screw 532 journalled through the motor mount 406, a lead nut 53 1 on said screw, and a spur gear 535 on the end of said screw and meshing with the pin gear 428 mounted on the shaft MB of the elevation motor 4H) (Figure 19). At the end of the switch actuator 526 (Figure 15) above the screw 532 a slot 538 is disposed horizontally. In addition, two oppositely disposed protrusions 549 and 542 extend into the limit switches 52% and 536, respectively. Extending above the lead nut 534 is a pin 544 adapted to move in the slot 533 between the ends thereof, causing the protrusion on the side of the actuator 526 to open its corresponding switch whenever the pin 5 moves against the corresponding end of the slot 538. This shuts oi? the elevation motor H0, permitting it to be actuated only in the reverse direction. The purpose of the limit switch 522 is to prevent the collision of the gear 214 (Figures and 11) with the gear H2 on either side thereof.

Having set forth the difierential gear assembly it is possible to describe the manner of operation with respect to the three degrees of rotation of the tongs 36 made possible by said assembly. The remaining elements not yet described which are disposed at the top of the differential gear assembly 49 are adapted to the closing of the jaws 38 on the tongs 3G, and will be described fully below. Considering one direction or" rotation at a time, the rotation of the tongs 3 3 about their longitudinal axis is governed primarily by the twist motor H2. Referring to Figure 16, if said motor alone is actuated in the clockwise direction, the motion is transmitted through the shaft 352 at a unit speed to the differential gear 458. The box 456, turning with said shaft, rotates the cage 46G, thereby transmitting the rotation to the side gear 456 in the same direction at two units of speed. The side gear 112 remains stationary because it meshes with the fixed spur gear M6. Consequently the motion is transmitted to the shaft 484 via the spur gear 482 which, having a diameter twice that of the gear 4H1, reduces the speed to one unit counterclockwise. Clearly this motion is transmitted from the shaft 436 to the worm 36 which rotates the worm gear 298 and the twist tube IE4 clockwise (Figure 17). At the lower end of said tube (Figure 10 the gear H2 rotates the gear wheel 262 which, in turn, rotates the gear 2M counterclockwise, which is the direction of the rotation of the jaws 38 about their longitudinal axis.

When the elevation motor 4!!! alone is actuated in a clockwise direction, the shaft 652 turning at a unit speed transmits the motion to the cage 459 of the differential gear 448. In this situation the side gear 456 is held motionless because the gear 466 meshes with the stationary gear 186. Hence the cage 460 rotates clockwise, causing the side gear 458 and the spur gear 468 to which it is attached to revolve clockwise at two units of rotation. This is transmitted to the central shaft M4 at the same speed counterclockwise by virtue of the gear 4'55 and to the gear 418 which in turn engages the large gear 492 whereby the two units of rotation are again reduced to one unit in the clockwise direction.

Accordingly, the motion is transmitted to the shaft 495 (Figure 14) which, by the pin clutch 595, is transmitted to the shaft 388 on which the worm 362 is disposed (Figure 17). From the worm 352 the motion is transferred counterclockwise through the worm gear 305 to the central tube I62. Returning to Figure 16 when the gear 4'55 is actuated by the gear 568 at two units of revolution the motion is transferred also to the gear 472. This motion is transmitted to the gear did through the gears 494 which re volve about their axis on either end of the shaft 352. From the gear m the motion moves to the worm 334, it being reduced to one unit of rotation by the larger gear 482 on the shaft 384. Through the worm gear 296 engaging the worm 365. the motion is transmitted to the tube 186 counterclockwise. Thus when the elevation motor M0 alone is actuated in the clockwise direction there results a counterclockwise rotation of the tubes I62 and I64 at the same speed. These rotations are transmitted separately to the gear wheels 200 and 292 counterclockwise (Figures 8, 1i) and 11), whereby the former wheel rotates the tongs 35 counterclockwise about the shaft i930 while the latter wheel rotates the gear 21 at the same speed clockwise in order to prevent the jaws 38 from rotating about their longitudinal axis (which would be the case if the gear wheel 262 did not turn). It is pointed out that if the gear wheel 25%) alone were rotated, and the gear wheel 232 remained stationary, the gear 215 would revolve about the gear wheel 2%? causing the jaws 38 to twist about the longitudinal axis of the tongs and thereby overturning any container between said jaws.

Returning to Figure 16 there remains the consideration of actuating the azimuth motor 458 while the motors 4H] and M2 remain motionless. In this event one unit of rotation of the motor 368 clockwise is transmitted directly through the shafts M8 and 356 to the worm 360 by which the worm gear 315 is rotated counterclockwise. In addition the gear 388 on the shaft 649 is rotated clockwise, transmitting said motion to the gear 468 at two units of rotation counterclockwise. This motion moves through the differential gear 448 to the gear 468 which turns clockwise. In turn the gear 416, revolving counterclockwise at two units of revolution, turns the gear MB counterclockwise and the gear 412 clockwise. The gear (3'13 transmits its motion to the gear 492 clockwise at one revolution, whereby the worm 362 (Figure 17) actuates the worm gear 386 counterclockwise. Further, the gear 412 rotating clockwise at two units or revolution, transmits said revolution through the difierential gear 1358 to the gear 6'16 in the reverse direction. Hence the gear 482 revolves clockwise at one unit of revolution, causing the worm 364 to drive the worm gear 296 in the counterclockwise direction. Thus by actuating the motor 488 clockwise the three worm gears 296, 3%, and 318 are actuated counterclockwise. Upon being transmitted through concentric tubes H30, H32 and IE4 the tongs 3S rotate about three axes, namely, the vertical axis of said tubes, the horizontal axis of the shaft I90, and the longitudinal axis of said tongs.

Clearly from the above analysis when two or more motors are actuated simultaneously, either clockwise or counterclockwise, the motions are resolved through the differential gears M8 and E59, resulting in varying speeds of rotation and direction about the three axes of rotation of the tongs 36.

There remains for consideration the mechanism by which the jaws 3B are actuated. Considering Figure 11 it was mentioned above that the rollers 256 and 258 are separated by the cone 223 when the latter is moved to the right, thereby closing said jaws. Conversely, when the cone 228 is moved to the left by the spring 236, the jaws 38 are opened with the aid of the spring 254. As was also mentioned above the cone 228 is urged to the right by the cord m, the other end which is secured to the lower end of the cable tube 2 !2 (Figure s). The cable tube H2 is sustained in position by the cord 352 (Figure 17) which passes over the pulley 344 on the shaft 346. As shown in Figure 15 each end of the shaft 346 is mounted in a block 556, secured at the top of the bridge 352. Central of the block 556 is a vertical slot 552 aligned with the aperture 356 directly over the cable tube 2E2. In this manner the cord 342 is mounted over the pulley 344 in said slot and is anchored to a post 555. On either side of the block 556 is disposed a pair of rollers 556 mounted on either end of a shaft 558 disposed in said block. The rollers provide support for a yoke 568 the arms of which extend along opposite sides of the block 556. In each arm is a longitudinal slot 562 (Figure 14) the sides of which glide over the periphery of the corresponding rollers 556. At the center of the yoke 56!! is a longitudinal bore 555 which is threaded to receive an elongated screw 566. On one side of the yoke 566 is a limit switch arm 568 the purpose of which will be described below.

Referring to Figures 15 and 18, the bridge 352 has two upright support members 516 and 512 integral therewith, one on either side. The members 576 and 552 have a longitudinal bore 514 and 5'16, respectively, centrally disposed therein which serve as terminals for two guide rods 518 and 586. The guide rods 513 and 580, being parallel to the screw 566, extend across the top of the difierential gear assembly 46 to the motor mount 566 to which the ends of said rods are secured in support elements 582 and 584, respectively, integral with said mount. Slidably disposed on the rods 51% and 586 is a tension bridge, generally indicated at 586, which comprises a cross piece 588 and a pair of arms 565 and 592 integral with said crosspiece and mounting the rods 578 and 586, respectively, at either end thereof. Around each rod 576 and 566 is a spring 59 and 596, respectively, each of which abuts a corresponding upright support member on one side and an arm of the tension bridge 586 on the other side. These springs, being calibrated to a given spring-rate, are adapted to function in cooperation with a series of limit switches for varying degrees of tension in the jaws 38 of the tongs 36, to be described below.

At the center of the crosspiece 565 is an aperture 598 that is aligned with the screw 566. This aperture supports a tension motor 656 extending from the side of the crosspiece 586 remote from the screw 566, and it supports an annular bearing housing 682 in which is disposed an annular bearing 664. The end of the screw 566 remote from the yoke 560 extends through the bearing 664. where it is secured by a flange 606 integral with said screw and abutting said bearing. This end of the screw 566 includes a brooched bore 638 which matches the end of the shaft of the motor 666. Accordingly, when the motor 666 is activated, the screw 566 turns within the yoke 565, drawing it and the cord 642 toward said motor. This operates to close the jaws 33 of the tongs 36. Contrarily, when the motor 666 is activated in the reverse direction, the screw 566 urges the yoke 566 to the left, thereby relieving '14 the tension in the cord 342 which act permits the jaws 38 to open.

Associated with the operation of the jaws 36 of the tongs 36 is a series of limit switches connected electrically to the motor 666 (Figure 21). These switches, disposed in two banks of three, are mounted in a pair of switch brackets 6 l 0 and 6I2 a,op the bridge 402 on opposite sides of the screw 566. The bank of switches mounted in the brackets 6H comprise switches 6M, 6l6, and 616 having a switch button 526, 622, and 6%, respectively. Similarly the bank of switches disposed between the switch bracket 6 l 2 comprise switches 626, 628, and 636, having buttons 632, 63 i, and 536, respectively. Extending from the crosspiece 568 on one side of the motor 66!! are two switch actuator screws 638 and 645, the ends of which are tapered and adapted to contact the switch buttons 62B and 622, respectively, when the tension bridge 536 is drawn towards the yoke 566. Likewise, on the crosspiece 588 on the other side of the motor 660 are disposed three switch actuator screws 642, 64 i, and 666 that are adapted to function with switch buttons 632, 634, and 636, respectively.

The combination of the springs 564 and 556 together with the aforementioned limit switches provides four degrees of tension in the of the tongs 36. These degrees are denoted arbin trarily by the switches 635, 6l6, 626, and 626 in increasing degrees. The purpose of the switch 61 is to sustain a closed circuit to the motor 666 until the crosspiece 586, moving along the guide rods 518 and 586, abuts the support elements 562 and 584. At this point the screw 536 moves off the button 626 to open the circuit to the motor 666. When the jaws 38 are open and it is desired to grasp an object between them with the least amount of tension possible by the manipulator, the operator at the control box (no-t shown in the drawing) selects a tension position connected to the switch 636. The selection is made by a tension selector 664, shown in Figure 21. Immediately the motor 696 rotates the screw 566 drawing the yoke 566 to the right and pulling the cord 342 with it over the pulley 345. This action closes the jawstfi upon the object to be handled at which point resistance is ofi'ered by said object to further closing of the jaws, whereupon the yoke 566 is drawn no further to the right. It is pointed out that until this moment the springs 564 and 596 have been fully extended. When the yoke 566 no longer moves to the right, the tension bridge 566 begins to move-to the left along the guide rods 51'6- and 586 against the springs 55s and 596. The force of the springs 594 and 596 against the tension bridge 586 is conveyed through the parts in tension to the jaws 38 with increasing degree until the switch actuator screw M6 travels far enough to the left to de ress the switch button 63-6. At this moment the desired tension in the tongs 36 are achieved and the motor 665 is shut off (Figure 15). If an increased degree of tension is desired, the operator makes his selection on the selector 654 connected to the switch 616. In this event the tension bridge 586 continues to move to the left until the switch actuator screw see depresses the button 622 of said switch at which position the circuit to the motor 656 is opened. Further, if still more tension in the jaws 36 is desired the selection is made to the switch 628. The circuit is closed and the motor 600 rotates the screw 566 within the yoke 566, causing the tension bridge 566 to compress the springs 594 and 596 with increasing 

